1. Field of the Invention
The invention concerns a damper-type flywheel, for instance a damper-type flywheel for a torque transmission device such as an automotive vehicle friction clutch; it is more particularly concerned with a flywheel of this type incorporating vibration damping means.
2. Description of the Prior Art
It is usual to insert torsional damper means at some point in the kinematic system constituted by transmission mechanisms which, in an automotive vehicle, extend from the motor to the wheel axles, in order to filter out vibrations that can arise anywhere along this kinematic system, in particular vibration due to the acyclic operation of the motor.
Such damper means are usually provided within the friction disk of the clutch.
However, it has already been proposed to incorporate such damper means in the flywheel fixed to the crankshaft of the motor and constituting the reaction plate of the clutch. This arrangement is particularly advantageous on a vehicle where it is necessary to minimize the noise occurring under load. A device of this kind is described in German patent application No. P 29 31 423, for example. The damper-type flywheel described in this document comprises two coaxial parts disposed to rotate relative to each other and between which are provided, on the one hand, circumferentially acting springs bearing at their ends against abutment means provided on the respective parts and, on the other hand, friction means. A system like this can give advantageous results in practice, especially in the case of the applications mentioned hereinabove, by virtue of the fact that the second and heavier part of the flywheel is on the output side of the spring and friction means within the kinematic system. Better filtering of vibration results from this. However, the coupling between the two parts of the flywheel is mechanically complex, especially because of the dry friction means, which are usually of two types. Firstly, there are friction means operative as soon as relative angular displacement occurs between the aforementioned two coaxial parts, and then there are friction means which become operative for a relatively high torque and in fact constitute a torque limiter.
The invention proposes a filter arrangement that is both simpler and more effective, utilizing damper means differing from those mentioned hereinabove. Generally speaking, the invention proposes to achieve the filtering effect by combining the action of circumferentially acting spring means with viscous damper means.